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# Fungrim entry: 569278

$\left(\left|a\right| \ne \left|b\right| \,\mathbin{\operatorname{and}}\, \left|b\right| = \left|2 d\right|\right) \implies \left(u = \operatorname{sgn}\!\left(a\right)\right)\; \text{ where } \left(d, u, v\right) = \operatorname{xgcd}\!\left(a, b\right)$
Assumptions:$a \in \mathbb{Z} \setminus \left\{0\right\} \,\mathbin{\operatorname{and}}\, b \in \mathbb{Z} \setminus \left\{0\right\}$
TeX:
\left(\left|a\right| \ne \left|b\right| \,\mathbin{\operatorname{and}}\, \left|b\right| = \left|2 d\right|\right) \implies \left(u = \operatorname{sgn}\!\left(a\right)\right)\; \text{ where } \left(d, u, v\right) = \operatorname{xgcd}\!\left(a, b\right)

a \in \mathbb{Z} \setminus \left\{0\right\} \,\mathbin{\operatorname{and}}\, b \in \mathbb{Z} \setminus \left\{0\right\}
Definitions:
Fungrim symbol Notation Short description
Abs$\left|z\right|$ Absolute value
Sign$\operatorname{sgn}\!\left(z\right)$ Sign function
XGCD$\operatorname{xgcd}\!\left(a, b\right)$ Extended greatest common divisor
ZZ$\mathbb{Z}$ Integers
Source code for this entry:
Entry(ID("569278"),
Formula(Where(Implies(And(Unequal(Abs(a), Abs(b)), Equal(Abs(b), Abs(Mul(2, d)))), Equal(u, Sign(a))), Equal(Tuple(d, u, v), XGCD(a, b)))),
Variables(a, b),
Assumptions(And(Element(a, SetMinus(ZZ, Set(0))), Element(b, SetMinus(ZZ, Set(0))))))

## Topics using this entry

Copyright (C) Fredrik Johansson and contributors. Fungrim is provided under the MIT license. The source code is on GitHub.

2019-06-18 07:49:59.356594 UTC